BubbleTax
LYNX · IBKR platform · Berlin

LYNX Broker Tax Reporting for Germany

Upload your FlexQuery XML and receive a complete German tax report — FIFO, ECB rates, foreign withholding tax, Anlage KAP. The calculation takes a few minutes.

LYNX has been the German-speaking gateway to the Interactive Brokers platform since 2006. BubbleTax adds one thing on top: the step from the IBKR data model to a German tax return. You keep your LYNX account and Berlin-based support; we handle FIFO, ECB conversion and KAP pre-filling.

BubbleTax is an independent provider and has no business relationship with LYNX. The name only describes which brokerage accounts the report works for.

Generate tax reportVisit LYNX website
  • BaFin-supervised
  • German-language support
  • Interactive Brokers platform

What your LYNX tax report looks like

Every line traceable back to the original IBKR booking. Stocks via FIFO, options, dividends with withholding-tax credit, FX gains under § 20 Abs. 2 Nr. 7 EStG.

Every sale is matched lot by lot to the corresponding purchase — with holding period, acquisition cost and the ECB rate of the original transaction.

LYNX + BubbleTax — how the two work together

Three steps, once a year. You stay in control of your data — we provide the German translation.

  1. 01

    LYNX provides the data

    You create a FlexQuery in your LYNX/IBKR account once and download the XML file. We've linked a step-by-step guide.

  2. 02

    BubbleTax does the German math

    We read every transaction, sort chronologically, apply FIFO, convert to euros at ECB reference rates and match withholding tax to dividends — fully traceable.

  3. 03

    You file in ELSTER

    You receive a PDF report with all values for Anlage KAP, KAP-INV and SO — ready to copy into ELSTER or hand to your tax advisor.

What BubbleTax computes from your LYNX XML

Every tax-relevant event of an IBKR account in one report — each with the corresponding legal basis.

TopicMethodLegal basis
Stocks & ETFsFIFO across accounts and years, adjusted for splits & spin-offs§ 20 Abs. 4 Satz 7 EStG
Options & futuresWriter logic, close-out, expiry, cash settlement§ 20 Abs. 2 Nr. 3 EStG
DividendsGross/net split, withholding tax matched per booking§ 20 Abs. 1 Nr. 1 EStG
Foreign withholding (US, CH, etc.)Credit up to DTA cap per source country, KAP line 41§ 32d Abs. 5 EStG
Foreign currency (USD, GBP …)FIFO per currency, ECB reference rate per booking§ 20 Abs. 2 Nr. 7 EStG
ETF advance lump sum & partial exemptionBasisertrag, partial exemption 30 % / 15 % / 60 % by fund type§§ 16, 20 InvStG

Frequently asked questions about LYNX tax filing

Does LYNX issue a German Jahressteuerbescheinigung?

No. Like all brokers on the Interactive Brokers platform, LYNX provides an English-language Activity Statement (FlexQuery), but no German tax certificate (Steuerbescheinigung) under § 45a Abs. 2 EStG. You have to determine the values for Anlage KAP yourself. That's exactly what BubbleTax was built for: a complete German tax report with all KAP lines from your LYNX FlexQuery.

Which taxes do I have to declare myself as a LYNX customer?

LYNX does not withhold German Abgeltungsteuer — you have to declare all capital income yourself in your German tax return. Specifically: gains and losses via FIFO, gross/net dividends, creditable withholding tax, foreign-currency gains over a 1-year holding period, ETF advance lump sum and derivatives. BubbleTax delivers every value directly in the KAP line structure.

How do I export the FlexQuery in LYNX?

In the LYNX account menu under "Reports / Statements", you create a FlexQuery for the tax year and download it as XML. Important: full tax-year period, all sections enabled (Trades, CashTransactions, OpenPositions, Transfers, CorporateActions). An illustrated guide is available on our upload page.

Is foreign withholding tax automatically credited at LYNX?

LYNX withholds foreign source taxes (e.g. 15 % on US dividends) at distribution — you see this as an FRTAX booking in your FlexQuery. The credit against your German Abgeltungsteuer per § 32d Abs. 5 EStG only happens during the German tax assessment. BubbleTax prepares the creditable amounts for Anlage KAP line 41 — per country with its DTA cap.

Do I also need Anlage KAP-INV for my LYNX account?

Yes, as soon as you hold ETFs or investment funds in your LYNX account. Anlage KAP-INV has been required since 2018 for advance lump sums, partial exemption and capital gains from funds. BubbleTax automatically separates values between KAP (stocks, options, withholding tax) and KAP-INV (fund income).

Are there differences from filing taxes for a direct IBKR account?

No — from the perspective of German tax law, LYNX data and IBKR data are identical, because LYNX uses the same platform as an Introducing Broker. The FlexQuery has the same format, same fields, same booking types. BubbleTax processes both the same way. The advantage of LYNX: German-speaking support from Berlin and BaFin supervision.

All questions and answers

Related topics
Foreign withholding tax & DTA credit

How the 15 % US withholding tax lands in Anlage KAP line 41.

FIFO calculation

How BubbleTax chains buy and sell bookings.

IBKR taxes hub

Everything German IBKR traders need to know about taxes.

In brief

The technical terms on this page, one paragraph each. Legal bases in brackets.

Flex Query
The configurable data export in the Interactive Brokers account management, also used by introducing brokers such as CapTrader or LYNX. BubbleTax needs it as an XML file with nine sections. Once set up, you export it again for each tax year.
FIFO
First In, First Out: when you sell, the units bought first count as sold first (§ 20 Abs. 4 Satz 7 EStG). This determines the acquisition cost and thus the gain or loss. IBKR uses other methods by default; BubbleTax rebuilds the positions under FIFO.
Vorabpauschale
A notional minimum return on fund units (§ 18 InvStG): the amount by which a fund's distributions in a calendar year fall short of the base return. It mainly affects accumulating ETFs that distribute little or nothing. BubbleTax calculates it from your holdings and distributions.
Partial exemption (Teilfreistellung)
A fixed share of fund income stays tax-free, depending on the fund type (§ 20 InvStG): 30 percent for equity funds, 15 percent for mixed funds, 60 percent for real estate funds, 80 percent for foreign real estate funds. It applies to distributions, the Vorabpauschale and gains from selling the units.
InvStG
The German Investment Tax Act governs how income from investment funds and ETFs is taxed at investor level: distributions, Vorabpauschale and disposal gains (§ 16 InvStG), with the Vorabpauschale (§ 18 InvStG) and partial exemption (§ 20 InvStG). These values belong in Anlage KAP-INV.
Spin-off
A corporate action: a company splits off a part and books shares of the new company into your account. For tax purposes it has to be determined whether the new shares replace the old ones and how the acquisition cost is allocated (§ 20 Abs. 4a EStG). BubbleTax detects spin-offs from the Flex Query section Corporate Actions.
Anlage KAP
The income tax return form for capital income: dividends, interest, gains and losses from shares and derivatives, creditable withholding tax. The report names the line for every value.
Anlage KAP-INV
The form for investment income without German withholding at source, as with IBKR: distributions, Vorabpauschale and gains from selling fund units (§ 16 InvStG).
Anlage SO
The form for other income. Relevant for investors in the case of private sales transactions under § 23 EStG; the report shows such values separately from capital income.

LYNX tax return: have it calculated first, then decide

Upload your FlexQuery XML and preview your report — free of charge.

Start free preview

No credit card · GDPR-compliant · EU hosting